In recent years, the success of food trucks has been on the rise in big cities across the United States. Mobile kitchens offer gourmet and ethnic food to customers they might not otherwise have reached. Some say social media outlets may be the major contributing factor to the success of the food truck.

Stephan Boillon is making his signature sandwiches with his sous-chef in this small kitchen in a truck. Lunch-time customers have formed a line outside it, in downtown Washington D.C., waiting to purchase a $7 sandwich.

“This is my favorite truck," says Jean Fundakowski, who works nearby. "It is Cuban sandwiches, so it's really spicy and they are not too expensive and they are really fast.”

Boillon, a restaurant chef for more than 20 years, tried to open his own traditional restaurant first.

“It was right around the time the banks crashed and the economy went down," he says. "So there was just no money. This is something I could open on my own.”

His food truck, El Floridano, hit the street less than two years ago.

Back then, there were about a half dozen food trucks in the area, Boillon says. Now he counts more than 70 and the number keeps growing. Most of the operators are aspiring entrepreneurs drawn to the business, like Boillon, for the low startup cost.

But Naceur Megra, who owns a Middle Eastern restaurant, jumped into the mobile business about two months ago for a different reason.

“It's a new trend in the city," says Megra. "So we are keeping up with things. So we have to keep up with stuff.”

Many food trucks are distinctively decorated and easily spotted in locations where office buildings crowd together. They try to please Washingtonian palates with simple but well-made ethnic foods.

“I tried the Thai truck. It's really authentic," says customer Katy Ricalde. "The barbeque is from South Carolina. I like southern barbeque. It is really authentic. I like that each one brings its own taste, something new. The flavors are really delicious.”

For customer Grant Collins, the ethnic food is the attraction. “I certainly think it is better value, particularly there is no service charge et cetera involved. I think the quality and the taste is as good if not better than is available in regular food outlets.”

The popularity of the food trucks is a concern for nearby restaurants, like Loeb's New York Deli.

“I do not wish ill on anybody, but it certainly makes it a little bit harder for everybody when you have that many food trucks in that park over there,” says deli owner Marlene Loeb.

The food trucks are also impacting traditional street vendors like Kasa Tehga, who has operated a hotdog cart at this corner for 18 years.

According to Boillon, food trucks have their own challenges, like the weather and frequent health inspections.

Jeff Kelly, who franchised his Eat Wonky food truck, is one of the founders of the Food Truck Association.

“Trucks at a minimum are required to be inspected twice a year in accordance with the D.C. Department of Health Regulations," says Kelly. "You have a health certificate posted from the Department of Health. In addition, on the street, the Metropolitan Police Department is quite frequently inspecting trucks.”

Since food trucks are always on the move, Kelly says staying in touch with customers through Facebook, Twitter and other social media outlets is critical.

“We communicate with our customers about where we are going to be on a given day, and how we are going to serve on a given day, and we get feedback from them on a continual basis."

Kelly says food trucks bring a vibrancy and an exciting new menu of dining options to the city.